Motorola V600

v600 with updated software or v551?

I got the v600 when it first came out and as with many people had problems. It sucked, tons of dropped calls, so I had it exchanged. I got a new v600 with an updated software package which fixed most of the bugs. I still have a few dropped calls but not nearly as many as before. With that in mind i've heard nothing but good things about the v551, including better reception. So should I update again or should I stick with what I've got?